Antenna housing



March 21 1950 E. B.y MGMILLAN ETAI. 2,501,072

` ANTENNA HOUSING Filed Aug. so, 1945 ARD B. M BY EDW HENRY RIBLET ATTORNEY w Patented Mar. 21, 1950 UNITED STATES PATENT OFFICE ANTENNA HDUSING Edward B. McMillan, Boston, and Henry J. Riblet, Cambridge, Mass., assgnors, by mesne assignments, to the United States of America as represented by the Secretary of War Application August 30, 1945, Serial No. 613,604

3 Claims. (Cl. Z50-33) The present invention relates to housings and more particularly to housings for electromagnetic energy radiating devices.

In many applications of radio aparatus it is desirable to enclose that portion of the apparatus which serves to radiate energy into space in order to protect it from the eiects of weather, rough handling or accidental blows, wind or other fluid pressures, and the like. The practicality of and necessity for such a housing increases as the wavelength of the transmitted energy decreases since an extremely high frequency transmitter will usually require a small, delicate antenna.

Accordingly, it is one object of this invention This skin material is chosen chieiiy for its mechanical qualities. It would be possible to construct the housing entirely of this substance; however it has been found that the radiation pattern of the antenna would suffer by reason of the unsatisfactory electrical characteristics of the material.

A compromise is made by making skin 5 thick enough to be reasonably rigid and thin enough so that the electrical pattern of the radiated energy is relatively undisturbed. To strengthen the housing further it is filled with a low-density material 6 which is inferior to the substance of which shell 5 is composed in strength, but

to provide a housing for radio antennas. l5 superior to it in dielectric characteristics.

Another object is to provide a streamlined A hole 1 is drilled into the filler material to antenna housing for use in arapidly moving fluid receive an antenna and may be lined with a medium. sheet 8 of the same material of which skin 5 is Still another object is to provide an antenna made. Due to the streamlined shape of the housing which will permit the radiation pattern housing, energy emitted from the antenna will of the antenna to be relatively undisturbed. encounter vdifferent thicknesses of solid material An additional object of the present invention depending upon the radial direction in which it is to provide a new and mproved antenna housing is propagated. This can be seen more clearly in that will have provision for balancing its elec- Fig. 2 in which a transverse section of the houstrical characteristics in various directions to suit ing of Fig. 1 taken along the line '2-2 is shown. the radiation pattern of the antenna. Clearly, radiation toward the blunt and wide These and further objects of the invention will front edge of the housing will pass through less be apparent to those skilled in the art upon referthickness of dielectric material than radiation ence to the following specification, claims, and toward the tapered rear, and radiation toward to the drawings in which: the sides will encounter even less. Since the Fig. 1 is a longitudinal cross-sectional view of one embodiment of the invention; and

Fig. 2 is a transverse cross-sectional view of the housing shown in Fig. 1.

Similar reference numerals pertain to the same parts throughout the drawings.

The antenna housing shown and described hereinafter is especially adapted for use with airborne, extremely high frequency radio apparatus, although the general scope of the invention is not necessarily limited to such an application.

Two considerations are paramount in the design and construction of van enclosure for any type of electromagnetic energy radiator. The rst is the mechanical strength of the material used, in order that the housing may perform its protective function, and the second is the electrical characteristic of the material, in order that the radiation pattern of the radiator will i not be impaired.

Referring now to Fig. 1, a shell, or skin, 5 of an at least partially wave-transparent material .is formed into a desired shape, which in this case is that of a tube with a streamlined cross-section.

impedance presented to the radiant energy is closely related to the thickness of dielectric substance through which it must pass, it can be seen that the radiation pattern of the antenna will be adversely altered.

Therefore holes or cavities IU, II, I2, I3, I4. I5, I6, and I'I are bored into the filler material in such a fashion as to substantially equalize the thickness of dielectric material in every direction radial to the antenna.

Plugs 20. 2I, 22, 23, 24, 25, 26, and 2! are inserted into the equalizing holes at certain noncritical points such as the center and the open endl as determined by the standing wave pattern on the antenna itself, in order to strengthen the structure. Finally, a retaining plug 30 is inserted into the end rof the housing in order to hold the ller material firmly in place.

In practice, it has been found that a material suitable for skin 5 is a laminate of Fiberglas with a stvrene copolymer and the ller material may be satisfactorily composed of low density Hycar OR, which is a compound of synthetic rubber and other substances. Any suitable means may be provided for securing the housing to the article intended to support and couple it.

It will be recognized by those skilled in the art that the full scope of the invention is not necessarily defined precisely by the details of the embodiment described hereinabove, but departures may be made therefrom Without exercise of inventive ingenuity. Hence, all such modifications and adaptations are claimed as may fall fairly within the spirit and scope of the hereinafter appended claims.

What is claimed is:

1. A housing structure for an electromagnetic energy radiator comprising, a relatively thin shell of partially wave-transparent material and of quasi-streamlined transverse contour uniformly distributed throughout its longitudinal axis, a solid substance filling said shell and of relatively low density but relatively superior dielectrically to said material and permeated with holes therein in predetermined directions, areas and lengths to equalize their inherent dielectric effects in designated radial directions, one of said holes being sized and situated in said substance for the placement of an antenna therein, said holes and substance being arranged about said antenna as to provide a substantial equalization of the attenuation by the radiant energy emitted from said antenna through said structure.

2. A housing structure `for an electromagnetic energy radiator comprising, a relatively thin shell of substantially wave-transparent material and of quasi-streamlined transverse contour uniformly distributed throughout its longitudinal axis, a substance filling said shell and of relatively low density and thickly deposited in said shell but relatively superior dielectrically as compared with said shell, said substance being permeated with parallel cavities therein in predetermined directions to equalize the inherent dielectric resistivity in designated radial directions, one of said cavities being situated among said other cavities in said substance for the longitudinal placement of an antenna therein, said cavities and substance being arranged to provide a substantial equalization of the attenuation by the radiant energy emitted from said antenna through said structure and means for closing the open portions of said cavities.

3. A housing for an antenna comprising a tubular skin or relatively thin dielectric material, and a filler of dielectric material within said skin and surrounding said antenna, said skin being asymmetrically disposed relative to said antenna and said skin having greater structural strength than said ller and said filler having better dielectric characteristics than said skin, and said filler being pierced by holes so disposed and shaped that the eiective thickness of the filler in every radial direction from the antenna is substantially the same, whereby the radiation pattern of the antenna is substantially undistorted by the asymmetrical eonguration of the housing.

EDWARD B. McMILLAN. HENRY J. RIBLET.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number' Name Date 2,202,380 Hollmann May 28, 1940 2,313,046 Bruce Mar. 9, 1943 2,293,112 Carlson Aug. 18, 1943 2,413,085 Tiley Dec. 24, 1946 2,429,601 Biskeborn Oct. 28, 1947 2,433,924 Riblet Jan. 6, 1948 

